Control system



P 1929- R. c. DEALE Q h 1,707,460

CONTROL SYSTEM Filed Dec. 29, 1924 INVENTOR BY Q 6 I ATTGRNEY Patented Apr. 2, 1929.

'UN'ITED. STATES PATENT-I oFrlc ROBERT C. DEALE, F PLAINFIELD, NEW JERSEY, ASSIGNOR T0 NILES-BEMENT-POND COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW EBSEY.

. CONTROL SYSTEM.

Application filed December 29, 1924. Serial No. 758,680.

My invention relates to control systems and partlcularly to control systems for operating planers and other machine tools.

One object of my invention is to provide a control system for a machine tool that shall govern a feed motor to effect feeding movements of the cutting tools at different rates of speed in a new and improved manner and that shall operate the feed motor to effect traverse 'movemeiit of the tools at different rates of speed.

Another object of my invention is to provide a control system for operating a machine tool having a reciprocating member that shall operate a pilot switch at one end of the stroke of the reciprocating member for operating a holding switch and that shall opcrate the pilot switch in a reverse direction at the opposite end of the stroke of the re-" ciprocating member for effecting operation .of the feed motor by means of the holding switch. I A further object of my invention is to provide aplaner control system of the above innew and improved means for traversing the cutting tools at different rates of speed.

' [In operating machine tools, and particularly in operating planers, it is desirable to control the feeding and the traversing movements of the cutting tools by means of an auxiliary .or feed motor which is operated from thesame source of 'power as the main feeding movements at a predetermined rate and is operated in a, reverse direction to. efiect feeding movements at a difierent rate, In controllingthe feedinotor, the'pilot switch, I at one end of the stroke of the reciprocating member, effects operation of a holding switch which is provided with a holding circuit.

dicate'd character that shall be provided with The holding circuit for the switch is normally'. closed and maintains the holding switch in operative position. At the opposite end of the stroke of the reciprocating member, the pilot switch efi'ects operation of a feed switch through the holdin switch. The feed switch effects operation 0 the feed motor. After a predetermined operation of the feed motor, the holding circuit for the holding switch is opened. A feed reverse switch is provided for reversing the connections of the pilot switch to the holding switch andto the feed switches in order to effect feeding movements at the opposite end of the stroke of the reciprocating member.

- In the copending application of Nicholas Marcalus, Serial No. 7 56,054, filed December 15, 1924, for a planer is disclosed a machine which is adapted to be operated-by a control system constructed in accordance with my invention. Moreover, in the application of Nicholas Marcalus, Serial No. 7 56,054, filed December 15, 1924, is disclosed .a switch of the type shown in this application which is preferable for'limiting the feeding'operation of the feed motor. 1 p

In the accompanying drawing: Figure 1 is a diagrammatic view of a planer 8 adapted to be operated by a control system constructed in accordance with my invention.

Fig. 2 is a diagrammatic view of a control. system, constructed in accordance with my invention. 4

Referring to Fig. 1- of the drawing, a planer is illustrated having a bed 1, a work-carrying table 2,and uprights 3. A suitable cross rail 4, which carries acutting tool 5, is mounted on the uprights 3. y A feed motor 6 is prej-v erably mounted on a bracket 7 which projects from-the cross rail 4. The feedmotor 6 controls the feeding and traversing movements of the cutting tool 5 in the manner described 05 in the application of Nicholas Marcalus, Se rial No. 756,054.

A main motor 8 which is controlled by a @pilot switch 9, is; rovided for reciprocating the table 2. The pilot switch 9 is supported on the bed 1 of the machine and is operated in accordance with the movement ofthe table 2. The table 2 carries two adjustable dogs 10 and 11, which engage levers 12 and 13 for is insulated from the switch arm-49 and in' operatin'g the pilot switch 9. The levers 12 and 13 areconnected to the pilot switch by means of links 14. The control'of the pilot switch by the planer table is well-known and further description is deemed unnecessary.

Referring to Fig. 2 of the drawing, the main motor 8 is shown comprising an armature 15, a commutator windin 16 and a shunt field-magnet winding 17. T e feed motor 6 comprises an armature 18, a shunt field-magnet winding 19 and a series field-magnet winding 20. The main motor 8 is controlled by two main switches 21 and 22, and an accelerating switch 23. The feed motor is con trolled by two feed switches 24 and 25 and an accelerating switch 26. The main switch 21 comprises an operating 'magnet 30, a holding magnet 31, and a switch arm 27 having two contact members 28 and 29 mounted thereon. The contact member 28 engages a stationary contact member 32 in the operative position of the switch arm and the contact member 29 engages a stationary contact member 33 in the released position of the switch arm. A pin 34 is mounted on the lever 27 for operating a switch 35 to insert a resistor 36 in the circuit shunt field-magnet winding 17 during the return stroke of the planer.

The switch 21 is operated to efi'ect a return stroke of the table 2 and the switch 22 is operated to effecta cutting stroke of the planer table. During the cutting stroke, a resistor 37 is included in the circuit of the shunt field-magnet winding 17 whereas during the return stroke the resistors 36 and 37 are included in the circuit of the shunt fieldmagnet winding. A switch 38 is closed by the switch arm 27 in the operative position of the switch 21 to-complete theenergizing circuit for the accelerating switch 23.

The main switch 22 comprises an energizing magnet 43, a holding magnet 44, and

a switch arm 40 having two contact members 41 and 42 mounted thereon. In the operative posit-ion of the switch arm, contact member 41 engages stationary contact member 45 and in the released position of the switch arm contact member 42 engages a'stationary contact member 46. In the operative position of the main switch 22, the switch arm 40 engages a resilient contact member 47 for completing a circuit to efi'ect operation of the accelerating switch 23.

The accelerating switch 23 comprises an operating magnet 48 and a switch arm 49 having two contact members 50 and 51 mounted thereon. The contact member 51 the released position "of the switch arm bridges two stationary contact members 52.

The contact member 50 engages a stationary contact member 53 in the operative position of the switch arm 49.

The feed switch 24 comprises an energizing auxiliary switch is operated by the switch arm 58 to prevent the operation of the feed switch 25 when the-feed switch 24 is in an operative osition.

The fee switch 25 comprises an energizing magnet 66, a holding magnet 67, and two switch arms 68 and 69. The switch arm 69 carries a contact member 70 which engages a stationary contact 'member 71 in the operative position of the switch. The switch arm 68 carries two contact members 72 and 73. In the released position of the switch, the

contact'member 73 engages a stationary contact member 74 and in the operative posi- -tion of the switch, thecontact member 72 engages stationary contact member 75. An auxihary switch 76 is operated by the switch arm 69 to prevent operation of the feed switch 24 when the feed switch 25 is in an operative position.

The accelerating switch 26 comprises an operating magnet 77 and a switch arm 78 having a contact member 79 mounted thereon. The contact member 79 engages a contact member 80 in the operative position of the switch. The coil 77 of the accelerating switch is connected across the armature of the feed motor. The switch serves to short circuit 23.-resistor 81 from the feedmotor circuit. A circuit breaker 82, comprising switch arms 83 and 84, is provided for connecting the circuits of the feed and the mainmotor to supply conductors 85 and 86.

The pilot switch 9 comprises contact segments 87, 88 and 89 which engage contact fingers 90 to 98, inclusii'c. The pilot switch controls the operation of main switches 21 and 22 and the accelerating switch 23 to govern the operation of the main motor 8 and controls the operation of the feed switches 24 and 25 to govern the operation of the feed motor 6.

A holding switch 100, comprising an op switch from a released position. I The holding circuit only energizes the magnet 101- sufficiently to hold the switch 100 in an operative position after operation thereof. The auxiliary feed switch 106 is disclosed and claimed in the copending application of Nicholas Marcalus, Serial No. 756,054.

A two pole double throw switch 107 is provided for reversing the connections of the pilot switch 9 to the holding switch 100 and the feed switches in order to reverse the end of the planer stroke at which the feeding operation takes place. The switch 107 comprises. two switch arms 108 and 109, which engage contact members 110 to 113, inclusive. A switch arm 114, which engages a contact member 115 and a' contact member 116, is controlled in accordance with the rate of the feeding. movement in the manner disclosed in. the copending application of Nicholas Marcalus, Serial No. 7 56,054. The switch arm 114 selectively operates either the switch 24 or the switch 25 and accordingly deter-v mines the direction of rotation of the feed motor 6.

Two push button switches 117 and 118 are provided for effecting traversing operation of feed motor,6 at different rates of speed. In the released position, the switch 117 bridges contact members 119 and in the operative position bridges contact members 120.

The switch arm 118 in the released position bridges contact members 121 and in the operative position bridges contact members 122.

Assuming the table 2 to be at the end of the cutting stroke, the dog 10 engages the lever 12 for operating the pilot switch 9. The pilot switch 9 is operated to bridge the contact fingers 97 and 98 by 'the contact segment 87. The contact segment 88 bridges the contact fingers 90 and'91 and the contact segment 89 bridges contact fingers 94 and 95. The bridging of the contact fingers 97 and 98 by the contact segment 87. completes a circuit for operating the main switch 21 to reversethe d1rectionofrotation of the main motor 8.

-The energizing circuit for the main switch 21 extends from the supply conductor 86 through the switch arm 84,.contact fingers 97 and 98, which are bridged by the contact segment 87, coil 30, switch arm 40, contact mem:

hers 42 and 46, holdingcoil 44, and the switch arm 83 to the suppl conductor 85. v

The main 'switc 1 21 completes a circuit through the main motor 8 which extends from the supply conductorthrough the switch arm 84, contact members 32 and 28, switch arm 27, resistor 130, winding 16, armature 15, switch arm 40, contact members 42 and 46, holding magnet 44,-and' switcharm 83 to thesupplyconductor 85. Upon operation of the main switch 21, the accelerating switch 23 is operated b a circuit which extends from one terminal 0 the armature 15 through the coil 16, contact fingers '90 and 91, which are bridged by the contact segment 88, operating magnet 48, switch 38, and the switch arm 40 to the other terminal of the armature 15. The accelerating switch 83 excludes the resistor 130 from the circuit of the main motor.

Upon operation of the accelerating switch 23.

the direct connection of the shunt field-mag net winding across the supply conductors is opened and the circuit extends through the resistors 36-and 37. Such circuit of the shunt field-magnet winding extends from the supply conductor 86 through the switch arm 84, resistors 36 and 37 winding 17. and the switch arm 83 to the supply conductor .85.

- Inasmuch as the resistors 36 and '37 are included in thecircuit of the shunt field-magnet winding, it is apparent the return stroke of the planer is effected at increased speed.

The bridging of the contact fingers 94 and by the contact segment 89 completes a circuit for o erating the holding switch 100. The circui through the operating magnet of the holding switch extends from the supply conductor 86 through the switch arm 84, contact members 94 and 95, which are bridged by the contact segment 89, switch blade 109, magnet 101, and the'switch arm-83 to the supply conductor 85. In the above circuit, it is assumed the switch 107 is in its lower position inorder to effect a feeding movement at the end of the return stroke. If the switch 107 is in its upper position, a feeding movement is effected at the end of the cut ting stroke. In the present position of the switch 107 no movement whatever is effected by the feed motor until the table 2 reaches the end of the return stroke.

At the end of the return stroke, the dog 11 engages the lever 13 for reversing the position of the pilot switch 9. In the reversed position of the pilot switch, the contact segbraking circuit is completed through the main motor 8. Such circuit extends through" the holding magnets 31 and 44 of the main switches 21 and 22 to prevent operation of such switches until the ynamic braking ourrent ceases to flow. The contact segment 87 is moved to bridge the contact fingers 90 and 91 for operating the accelerating switch 23 upon operation of the main switch 22.

The contact segment 88 bridges contact fin- I gets 92 and 93 for operating the main switch 22. The energizing circuit for the main switch 92 and 93, which are bridged by the contact "segment 88, magnet 43, switch arm 27, contact members 29 and 33, magnet 31, and the switch arm '83 to the supply conductor 85. The

. main switch 22 is operated and a circuit is completed through the main motor 8 which extends from the supply conductor 86 through the switch arm 84, contact members 45 and 41, switch arm 40, armature 15, compensating winding 16, accelerating resistor 130, switch arm 27, contact members 29 and 33, holding coil 31, and the switch arm 83 to the supply conductor 85. The main motor 8 is operated in a reverse direction for operating the table 2 toeifect a cutting stroke.

The accelerating magnet 23 is operated by a circuit which .extendsfrom one terminal of the armature 15 through the winding 16, contact members 90 and 91, which are bridged by the contact segment 87, coil 48, contact member 47, and the switch arm 40 to the other terminal of the armature 15.-

Thecontact segment 89 is moved out of engagement with the contact finger 94 and into engagement with the contact finger 96. The separating of the contact segment 89 from the contact fingers 94 opens the energizing circuit for the holding switch 100. However, a holding circuit is normally closed through the coil 101 of the switch 100 so that the switch ismaintained in an operative position. The holding circuit for the switch 100 extends from the supply conductor 86 through the switch arm 84, switch 106, resistor 105, coil .101, and the switch arm 83 to the supply conductor 85.

The bridging of the contact fingers 95 and 96 by the contact segment 89 completes a circuit through the holding switch 100 for operating the feed switch 24. The circuit extends from the supply conductor 86 through the switch arm 84, contact members 95 and 96, which are bridged by the con-tact 89, switch arm 108, contact members 104 and 103, switch arm 102, switch arm 114, contact member 115, contact members 119, which are bridged by the switch 117, coil 55, switch 76, and the switch arm 83 to the supply conductor 85. The feed switch 24 is operated and a circuit is completed for operating the feed motor 6. The circuit through the feed motor extends from the supply conductor 86 through the switch arm 84, series field-magnet winding 20, accelerating resistor 81, con- .tact members 64 and 61, switch arm 57. armad ture 18, switch arm 58, contact member-s59 and 60, and the switch arm 83 to the supply conductor 85.

The feed switch 24 is released to stop the feeding movement by releasing the holding switch 100.- The holding switch 100 is released by opening the holding circuit which extends through the switch 106. The switch 106, which serves as a limit, is operated by the feed motor and accordingly is operated at only one end of the stroke. The switch 106, which is included in the holding circuit through the coil 101, is disclosed in the companion application of Nicholas Marcalus, Serial No. 756,054, and comprises a notched disk 131 which engages two contact members 132 and 133. Upon slight rotation of the disk 131, the disk is separated from the contact members 132 and 133. Such momentary opening of the holding circuit permits the release of the switch 100 and the release of the feeding switch to stop the feed motor.

The switch arm 114 is maintained in engagement with the contact member 115 through a certain range of feeding movements. When the rate of feeding is raised above a predetermined-point, the switch arm 114 is moved into engagement with the contact member 116. The operation of the switch 114 is described in the copending application of' Nicholas Marcalus Serial No.

' 756,054. If the switch arm 114 is in engagement with the contact member 116, the feed switch 25 is operated'in place of the feed switch 24 and the feed motor 6 is operated in a reverse direction. The energizing circuit for the feed switch 25 extends from the supply conductor 86, through the switch arm 84, contact members 95 and 96 which are bridged by the contact segment 89, switch arm 108, contact members 103 and 104, switch arm 102, switch arm 114, contact member 116, contact members 121, which are bridged by the switch 118, magnet 66, switch 65, and the switch arm 83 to ductor 85.

The circuit completed by the switch 25 through the feed motor extends from the supply conductor 86, through the switch arm 84, series field-magnet winding 20, resistor 81, contact members 75 and 72, switch arm 68,

the supply conarmature 18, switch arm 69, contact members 70 and 71, and switch arm 83 to the supply conductor 85. The coil 77 of the accelerating switch 26 is connected across the armature 18. The switch 26 serves to short circuit the resistor 81. As above set forth the feed motor 6 is operated in one direction to efiect feeding movement at one rate and is operated in a reverse direction to effect feeding movements at a different rate. Upon release of either the feed switch 24 or the feed switch 25, a dynamic braking circuitis completed through the feed motor. The 'ynamic braking circuit extends from one terminal of the armature 18, through the In case it is desired to effect traverse movement of the feed motor 6, the switch 117 or the switch 118 is operated according to the rate of traversingmovement that is desired. Upon operation of the switch 117, a circuit is completed for operating the feed switch 25.. Such circuit extends from the supply conductor 86 through the switch arm 84, contact members 120, which are bridged by the switch 117, magnet 66, switch 65, and the switch arm 83 to the supply conductor 85. The feed motor is continuously operated at a predetermined direction and a traversing movement is effected at a predetermined rate.

the feed switch 24 is energized for reversing the direction of rotation of the feed motor 6 and accordingly for varying the rate of the traversing movement. Upon operation of i the switch 118, a circuit is completed from the holding switch 100. .The switch 106- the supply conductor 86 through the switch arm 84, contact members 122, which are bridged by the switch 118, contact members 119, which are bridged by the switch 117, magnet 55, switch 7 6, and the contact arm 83 to the supply conductor 85.

In the above system, it will be noted the switch 107 serves to determine the end of the stroke at which a feeding movement by the motor 6 will be effected. The switch arm 114 determines the direction of rotation of the motor 6 during the feeding-movement and accordingly determines the rate of the feedmg movement. The pilot switch 9 at one end of the stroke efiects operation of the holding switch and at the opposite end of the stroke operates one of the feed switches through which is operated by the feed motor, serves to limit the extent of the feeding movement.

Modifications in the system and in the arrangement and location of parts may bemade within the spirit and scope of my invention and such modifications are intended to be covered by the appended claimsu,

her for operating the holding switch at one end of thevstroke ofthe reciprocating member, a holding circuit for holding the holding switch in operated position upon operation by said pilot switch, and means comprising a circuit completed by said pilot switch at the opposite end of the stroke of the recipro- V cating member for efiectingpperation of the motor through the holding switch.

a 2. In a .control system, the combination with a reciprocating member, and a motor,

of an auxiliary switch for operating the motor, a holding switch, means comprising a pilot switch operated by the rec procating In case the traverse switch 118 is operated,

member for operating the holding switch at one end of the stroke of the reciprocating member, a holding circuit for holding the holding switch in operated position upon operation by said pilot switch, and a circuit completed by said pilot switch at the opposite end of the stroke of the reciprocating member for operating the auxiliary switch through the holding switch.

3.-In a control system, the combination with a reciprocating member, and a motor, of auxiliary switches for operating the motor in a forward and in a reverse direction, a holding switch, means comprising a pilot switch operated by the reciprocating memher for operating the holding switch at one end ofithe stroke of the reciprocating memher, a holding circuit for holding the holding switch in operated position .upon operation by said pilot switch,-and acircuit completed by said pilot switch at the opposite end of the stroke of the reciprocatin member for operating one of the auxiliary switches through the holding switch. p 4. In a control system, the combination with a reciprocating member, and a feed motor, of auxiliary switches for operating the feed motor in a forward and in a reverse direction, a holding switch having a normally closed holding clrcuit, means comprislng a pilot switch operated by the reciprocating member for operating the holding switch at one end of the stroke of the reciprocating member and for operating one of the auxiliary switches throu h the holding switch at the opposite end of the reciprocating mem-- ber stroke, and means for opening said .holding circuit to release the holding switch and limit the movement of the feed motor after a predetermined operation thereof.

5. In a control system, the combination with a rcciprocatin member, a motor, and auxiliary switches o holding switch having a normally closed holding circuit, means eomprising'a pilot switch operated by the reciprocating memr operating the motor in a forward and in a reverse direction, of a her for operating the holding switch at one Y end ofthe stroke of the reciprocating member and for operating one of the auxiliary switches through the holding circuit at the opposite end of the reciprocating member stroke, and a switch for reversing the connections of the auxiliary switches to the holding switch to reverse the direction of rotation of the. motor when operated by the pilot-- switch. I

6. In a control system. for a machinetool, the combination with a reciprocating memher, a feed motor, and feed switches for operating the feed motor ina forward and in a reverse direction, of a holding switch having a normally closed holding circuit, means comprising a pilot switch operated b the reciprocating member for. operating the olding switch atone end of the stroke of the reci' rocating member and for operating one 0 the feed switches through the holding circuit at the opposite end of the reciprocating member stroke, and a switch for reversing the connections of the pilot switch to the holding switchto eflect a feeding movement at the opposite end of the stroke of the reciprocating member.-

7. In a control system for a machine tool, the combination with a reciprocating member, a feed motor, and feed switches for operating the feed motor in a, forward and in a reverse direction, of a holding switch having a normally closed holding circuit, means comprising a pilot switch operated by the reciprocating member' for operating the holding switch at one end of the stroke of the reciprocating member and for operating one of the feed switches through the holding circuit at the opposite end of the reciprocating membcr stroke, a switch for reversing the connections of the feed switches to the holding switch to reverse the direction of rotation of and stop the feeding movement of the feed motor, and means for selectively operating the feed switches to effect traversing movev ment at different rates of speed.

10. 1n a control system for a machine tool, the combination with a reciprocating. me i.- ber, a feed motor, and a feed switch for operating the feed motor, of a holding switch having a normally closed holding circuit, means comprising a pilot switch operated by the reciprocating member for operating the hold ing switch at one end of the stroke of the reciprocating member and for operatin r the feed switch through the holding swit h at the opposite end of the stroke of the reciprocating member, and means for opening the holding circuit to release the holding switch and stop the feeding movementof the feed motor after apredetermined feeding move" ment. i

11. In a control system for a machine tool,

the combination with a reciprocating mem-- ber, a feed motor, a feed switch for operating the feed motor in a forward direction to efthe feed motor wh t d b th il t fect feeding movement of the cuttin tool at switch and a switch for reversing the connections of the pilot switch to the holding switch 'to eflfect a feeding movement at the opposite end of thestroke of the reciprocating member. I I

8. In a control system for a machine tool, the combination with a reciprocating memher, a feed motor, and feed switches for operatmg the feed motor in aforward and in a reverse direction to effect a tool feed at different rates, of a holdin switch having a normally closed holding circuit, means comprising a pilot switch operated'by the reciprocating member for operating the holding switch at one end of the stroke of the reci rocrating member and for operating one o the feed switches through the holding switch at the opposite end of the reciprocating member stroke, and means for selectively operating the feed switches to effect traversing movement at different rates of speed.

9. In acontrol system for a machine tool, the combination with arecip-rocatingrhemher, a feed motor rotating in one direction to effect feeding at a predetermined rate and rotating in a reverse direction to efiectfeeding at a differentiate, and feed switches for operating the feed motor in a forward and 'in a reverse direction to efl'ect feeding movement at different rates, of a holding switch I having a normally closed holding circuit, means comprising a: pilotswitch operated by the reciprocating member for operating the holding switch at one end of the stroke or the reciprocating member and for operating one of the feed switches throu h the ho ding switch at the opposite end 0 the reciprocating member stroke, means for o ening the holding circuit to release the hol ing SItVltCh one rate of speed, and a second feed switch for operatin the feed motor in a reverse .direction to e ect a feeding movement of the cutting tool at a'diflerent rate of speed, of a holding switch, and means comprising a pilot switch operated by the reciprocating member for operating the holding switch at one end of the stroke of the reciprocating member and for o eratin one of said feed switches throu h t e hol ing switch atthe opposite end 0 the stroke of the reciprocating member.

12. In a control system, the combination with a motor, a ,feed switch'for operating the motor, and a holding switch, of means comprisin a pilot switch'operated to one position or operating the holding switch, a holding circuit for holding the holding switch inoperated position upon operation by, saidpilot switch and a circuit completed by said pilot switch in a reverse position for operating the feed switch through the holding switch.

13. In a control system for a machine tool, the combination with a reciprocating member, a main motor for operating the reciprocatin member, a feed motor, and a pilot switc ber-for controlling the main and the feed motor, of two feed switches for operating the feed motor in a forward and in a reverse direction, a holding switch, means comprising said pilot switch for operating the holding switch at oneend of the stroke of the reci rocatin member, a holding circuit for,

operated by the reciprocating mem-- holding switch, means'comprising said pilotswitch for operating the holding switch at one end of the stroke of the reciprocating 4 member, a holdingcircu'it for holding the holding .switch in operated position upon operation by said pilot switch, a circuit completed by said pilot switch in a reverse pdsitionat the other end of the stroke of the reciprocating member for operating one of the feeding switches through the holding switch and a switch for reversing the connections of i the feed switches to the holding switch to reverse the direction of rotation of the feed motor when operated by the pilot switch.

'15. In a control system for a machine tool, thecombination with a reciprocating member, a main. motor for operating the reciprocating member, a feed motor, and, a pilot switch operated by the reciprocating member for controlling the main motor, of two feed switches for operating the feed motor in a forward and in a reverse direction, a holding switch, means comprising said pilot switch for operating the holding switch at one end of the stroke of the reciprocating member, a holding circuit for holding the holding switch in operated position upon operation by said pilot switch, a circuit completed by said pilot switch in a reverse position at the other end of the stroke of the reciprocating member for operating one of the feed switches through the holding switch, and a switch for reversing the connections of the pilot switch to the holding switch toeffect a feeding movement at the opposite end of the stroke of the reciprocatingmember. I

16. In a control system for a machine tool, the combination with a reciprocating memher, a main motor for operating the reciprocating member, a feed motor, and a pilot switch operatedby the reciprocating member. for con-trolling the main motor, of twofeed switches for-operating the feed motor in a forward and in a reverse directioma holding switch, means comprising said pilot switch,

for operating the holdingswitch at one end of-the stroke of the-reciprocating member,-

aholding circuit for holding the holding switch in operated position upon operation by saidpilot' switch, a circuit completed by said pilot switch in a reverse position at the other end of the stroke of. the reciprocating member for operating one of the feed switches through the holding switch, a switch for reversing the connections of the feed switches to the holding switch to reverse the direction of rotation of the feedmotor when operated by the pilot switch, and a switch for reversing the connections of the pilot switch to the holding switch to effect a feeding movement at the' opposite end of the stroke of the reciprocating member.

17. In a planer control system, the combination comprising a main motor, a table reciprocated by said main motor, a feed motor operated at one end only of the table stroke, I

means operated by said table for completing a circuit to operate the feed motor, and a limit switch operated by the feed motor at only one end of the table stroke for limiting the move ment of ,the feed motor.

18. Ina planer control system, the combination comprising a main motor, a table reciprocated by said main motor, a feed motor,

.a pilot switch operated by said table at each end of the table stroke for controlling the main motor, a limit switch for limiting the operation of the feed motor, meansgforoper ating the limit switch at only one end of the table stroke, and means controlled by the pilot switch for operating the feed motor at one end only of the table stroke to effect feeding movements.

19. In a planer control system, the combination comprising a reciprocating table, a feed motor operated at only one end of the ,motor, and a limit switch operated at only one end of'the table stroke for limiting the movement of the feedv motor.

table stroke, a pilot switch operated in accordance with the movement of the table,

; 20. In a planer control system, the combination comprising a reciprocating work table, a feed motor, means for automatically operating the feed motor at one end only of the table stroke, and a limit switch for limiting the feeding movements of the feed motor and operated at only one end of the table stroke by the feed motor.

21. In a planer control system, the combination comprising a reciprocating table, In. feed motor for effecting a feeding movement at only one end of the table stroke, a limit switch for limiting the feeding movement of the feed motor and operated at only one end 9f the table stroke by. the feed motor, a pilot switch operated in ccordance with the movement of the table, a (1 means operated by the pilotswitch at one end of the table stroke for preparing a circuit to operate the feed motor and operated at the other end of the stroke 4 for completing the circuit to operate the feed motor.

nation comprising a reciprocating table, a feed motor, a pilot switch operated in accordance with the movement of the table, a limit switch for limiting the operation of the feed motor, means for operating the limit switch at only one end of the table stroke, means for operating the feed motorby the pilot switch only at one end of the table stroke and means comprising an auxiliary switch for selecting the end of the stroke at which operation of the feed motor and the limit switch is effected.

23. In a planer control system, the combination comprising a reciprocating table, a feed motor, a pilot switch operated in accordance with the movement of the planer table, means operated by the pilot switch at one end of the table stroke for preparing a circuit for operating the feed motorand operated by the pilot switch at the opposite end of the table stroke for completing the feed motor operating circuit, and means comprising a limit switch operated by the feed motor for limit' ing the operation of the feed motor.

24. In a planer control system, the combination comprising a reciprocating table, a feed motor operated only at one end of the table stroke, a pilot switch operated at each end of the table stroke, and means operated by the pilot switch at oneend of the table stroke for preparing a circuit to operate the feed motor and operated at the opposite end of the tablestroke for completing the circuit to operate the feed motor.

25. In a planer control system, the combination comprising a reciprocating table, a feed motor, a limit switch for-limiting the operation of the feed motor, means for operating the limit switch at only one end of th table stroke, a pilot switch operated at each end of the movement of the table for operating the feed motor only at one end of the table stroke, and means for selecting the end of the table stroke at which operation of the feed motor and the limit switch takes place.

I In testimony whereof, I hereto afiix my signature. V

ROBERT C. DEALE. 

